Most antennas heretofore used in cars were pole-type antennas configured to project to the exterior of the car during signal reception. Such an outwardly projecting configuration often invites its destruction. Such a prior art antenna is not configured to receive all different broadcasting bands, i.e. AM, FM and TV bands, and a car requires two or more antennas for reception of different bands. Many antennas outwardly projecting from the car body usually spoil the car appearance. In order to improve the appearance, some cars are provided with a glass antenna. However, since such a glass antenna, although expensive, is not configured to receive all different bands, a single car must use pole-type antennas in addition to the glass antenna in most cases.
There is another antenna of this type which is disclosed in Japanese Utility Model Laying-Open Publication No. 62-75615 which uses ferrite bars having pickup coils wound thereon to pick up a high frequency signal induced in a car roof or other body portion of the car at the boundary between the roof and a pillar portion.
However, since signals passing from the roof to the pillar portion, if any, are weak waves, the antenna must be mounted near the roof, etc. Beside this, the antenna cannot receive signals unless a booster is connected. Also when the booster is used, noises increase during reception of weak broadcasting waves, and hence degrades the signal-to-noise ratio. This necessarily results in signal reproduction difficult to hear. Further, since a significantly wide band amplifier is required to amplify AM, FM and TV bands, this also invites a deterioration of the signal-to-noise ratio and an increase of the manufacturing cost.
In order to establish a complete non-directivity by disposing ferrite bar cores in a crossing relationship and by connecting pickup coils, it is necessary to shift the phase of the induced voltage of one of the coils by .pi./2 for subsequent signal composition. However, it is a very difficult technology to shift the phase throughout a wide band. Further, since most car bodies are arcuated at the boundary between the roof and the pillar portion, it is difficult to reliably mount and hold such an antenna there.